diff options
Diffstat (limited to 'src/boot/efi/linux.c')
| -rw-r--r-- | src/boot/efi/linux.c | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/src/boot/efi/linux.c b/src/boot/efi/linux.c new file mode 100644 index 0000000..5b4c085 --- /dev/null +++ b/src/boot/efi/linux.c @@ -0,0 +1,127 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <efi.h> +#include <efilib.h> + +#include "linux.h" +#include "util.h" + +#define SETUP_MAGIC 0x53726448 /* "HdrS" */ +struct SetupHeader { + UINT8 boot_sector[0x01f1]; + UINT8 setup_secs; + UINT16 root_flags; + UINT32 sys_size; + UINT16 ram_size; + UINT16 video_mode; + UINT16 root_dev; + UINT16 signature; + UINT16 jump; + UINT32 header; + UINT16 version; + UINT16 su_switch; + UINT16 setup_seg; + UINT16 start_sys; + UINT16 kernel_ver; + UINT8 loader_id; + UINT8 load_flags; + UINT16 movesize; + UINT32 code32_start; + UINT32 ramdisk_start; + UINT32 ramdisk_len; + UINT32 bootsect_kludge; + UINT16 heap_end; + UINT8 ext_loader_ver; + UINT8 ext_loader_type; + UINT32 cmd_line_ptr; + UINT32 ramdisk_max; + UINT32 kernel_alignment; + UINT8 relocatable_kernel; + UINT8 min_alignment; + UINT16 xloadflags; + UINT32 cmdline_size; + UINT32 hardware_subarch; + UINT64 hardware_subarch_data; + UINT32 payload_offset; + UINT32 payload_length; + UINT64 setup_data; + UINT64 pref_address; + UINT32 init_size; + UINT32 handover_offset; +} __attribute__((packed)); + +#ifdef __x86_64__ +typedef VOID(*handover_f)(VOID *image, EFI_SYSTEM_TABLE *table, struct SetupHeader *setup); +static VOID linux_efi_handover(EFI_HANDLE image, struct SetupHeader *setup) { + handover_f handover; + + asm volatile ("cli"); + handover = (handover_f)((UINTN)setup->code32_start + 512 + setup->handover_offset); + handover(image, ST, setup); +} +#else +typedef VOID(*handover_f)(VOID *image, EFI_SYSTEM_TABLE *table, struct SetupHeader *setup) __attribute__((regparm(0))); +static VOID linux_efi_handover(EFI_HANDLE image, struct SetupHeader *setup) { + handover_f handover; + + handover = (handover_f)((UINTN)setup->code32_start + setup->handover_offset); + handover(image, ST, setup); +} +#endif + +EFI_STATUS linux_exec(EFI_HANDLE *image, + CHAR8 *cmdline, UINTN cmdline_len, + UINTN linux_addr, + UINTN initrd_addr, UINTN initrd_size, BOOLEAN secure) { + struct SetupHeader *image_setup; + struct SetupHeader *boot_setup; + EFI_PHYSICAL_ADDRESS addr; + EFI_STATUS err; + + image_setup = (struct SetupHeader *)(linux_addr); + if (image_setup->signature != 0xAA55 || image_setup->header != SETUP_MAGIC) + return EFI_LOAD_ERROR; + + if (image_setup->version < 0x20b || !image_setup->relocatable_kernel) + return EFI_LOAD_ERROR; + + addr = 0x3fffffff; + err = uefi_call_wrapper(BS->AllocatePages, 4, AllocateMaxAddress, EfiLoaderData, + EFI_SIZE_TO_PAGES(0x4000), &addr); + if (EFI_ERROR(err)) + return err; + boot_setup = (struct SetupHeader *)(UINTN)addr; + ZeroMem(boot_setup, 0x4000); + CopyMem(boot_setup, image_setup, sizeof(struct SetupHeader)); + boot_setup->loader_id = 0xff; + + if (secure) { + /* set secure boot flag in linux kernel zero page, see + - Documentation/x86/zero-page.txt + - arch/x86/include/uapi/asm/bootparam.h + - drivers/firmware/efi/libstub/secureboot.c + in the linux kernel source tree + Possible values: 0 (unassigned), 1 (undetected), 2 (disabled), 3 (enabled) + */ + boot_setup->boot_sector[0x1ec] = 3; + } + + boot_setup->code32_start = (UINT32)linux_addr + (image_setup->setup_secs+1) * 512; + + if (cmdline) { + addr = 0xA0000; + err = uefi_call_wrapper(BS->AllocatePages, 4, AllocateMaxAddress, EfiLoaderData, + EFI_SIZE_TO_PAGES(cmdline_len + 1), &addr); + if (EFI_ERROR(err)) + return err; + CopyMem((VOID *)(UINTN)addr, cmdline, cmdline_len); + ((CHAR8 *)(UINTN)addr)[cmdline_len] = 0; + boot_setup->cmd_line_ptr = (UINT32)addr; + } + + boot_setup->ramdisk_start = (UINT32)initrd_addr; + boot_setup->ramdisk_len = (UINT32)initrd_size; + + linux_efi_handover(image, boot_setup); + return EFI_LOAD_ERROR; +} |